A new study, however, suggests winter weight gain may in part be beyond our control – and rather a function of winter’s sunlight deficit. The study found that sunlight can shrink fat. Samples of human subcutaneous fat were essential to this serendipitous discovery.
University of Alberta researchers were initially studying how to make fat cells produce insulin in response to light to help diabetes patients, according to Folio, the University of Alberta journal. The researchers discovered along the way that fat cells shrink when exposed to the blue light emitted by the sun. They followed up by taking samples of subcutaneous white adipose tissue (scWAT) from patients undergoing weight loss surgery.
“When the sun’s blue light wavelengths—the light we can see with our eye—penetrate our skin and reach the fat cells just beneath, lipid droplets reduce in size and are released out of the cell,” Peter Light, senior author of the study and professor of pharmacology, told Folio. “In other words, our cells don’t store as much fat.”
“If you flip our findings around,” he said, “the insufficient sunlight exposure we get eight months of the year living in a northern climate may be promoting fat storage and contributing to the typical weight gain some of us have over winter.”
What works in the lab, of course, doesn’t necessarily translate to the scale. But you never know. Blue light does reliably wake us up.
“Well, perhaps that pathway—exposure to sunlight that directs our sleep-wake patterns—may also act in a sensory manner, setting the amount of fat humans burn depending on the season,” Light said. “You gain weight in the winter and then burn it off in the summer.”
For studies like this that require human biospecimens, a wide range of human tissues, fluids and cells, are available through the iSpecimen Marketplace, an online platform that helps researchers quickly obtain the biobanked or prospectively collected tissue, biofluids and cells they need from the patients they want. Researchers can specify patient demographics, diagnoses, medications, procedure history, outcomes or specific test result ranges.
Clearly there’s more we need to learn on how sunlight and fat interact. In the meantime, we might want to keep that gym appointment.